This research is to clarify the biological meanings of benthic foraminiferal test morphology through culture experiments. Culture experiments were made under the condition that water temperature, salinity, dissolved oxygen contents, light intensity, and other environmental factors were precisely controlled.(1) Culture systems: Benthic foraminifera, which were collected from many places around Japanese Islands, are maintained in the laboratory for culture experiments. Three different kinds of stock cultures are running in the laboratory: rough culture, raw culture and clone culture. Rough culture is a culture which keeps many species with natural bottom substrate. Raw culture is a stock of single species which is picked up from populations of rough culture.Clone culture is a stock of cloned population having a same genetic composition.(2) Culture experiments under controlled environments: Culture experiments were made for three species, Trochammina hadai, Ammonia beccarii, Glabratella o
… Morepercularis. Growth rates were changed according to temperature and salinity of culture water. However, test morphology is not changed. Test morphology was changed in relation to the dissolved oxygen contents in culture water. Periphery of a test is smoothed under the low oxygen environment. In contrast, periphery is lobated under the high oxygen environment. Pore diameters of Ammonia beccarii also changed with the oxygen contents in culture water. A. beccarii made large pores under the low oxygen environments. These results show that dissolved oxygen content is strongly affect to test morphology of benthic foraminifera. Deep-sea foraminifera which were collected from Sagami Bay are cultured under the conditions that both hydroaulic pressure and food contents are controlled. Deep-sea benthic foraminifera were well grown in high hydroaulic pressure and high food contents.(3) Breeding experiments: Breeding experiments of Glabratella opercularis were succeeded to make plastogamic pairs. Lots of daughter cells were born from plastogamic pairs. Less